Sticky calipers - ABS pump faut ?!

[DamirGTI 342]

Struggling big time with this one , starting to feel foamy epileptic mouth .

 

Not a PSA , but Vauxhall .

 

Anyone ever had dragging front brakes/calipers on any brand make or model , with the root cause being bad ABS pump ? 

Or possibly bad master cylinder ? (which i know is quite a bit rare , but also happens)

 

Any ideas visions thoughts - more than welcome !! , as i'm out of my mind with this one , left with just the two (expensive) options to try .

 

Thanks !

D

[Thijs_Rallye 87 4 Cars]

Well since Vauxhall is being owned by PSA (or should I say Stellantis) now I guess it isn't really offtopic . What model and year are you talking about, maybe I can dig something up.

[DamirGTI 342]

It's Corsa D , 1.2 16v ("eco flex" engine) , 2012 year .

 

Symptoms - dragging front brakes (only front ones) .

 

All is fine till driving on kinda level road (like fast dual motorway or autobahn) with not using the pedal more than half way pressed nor braking hard - wheels/brakes are nice and cold .

 

However , driving downhill/incline and pressing the pedal more often and especially applying harder more than half way - wheels/brakes are melting hot !!

 

Interestingly , it starts "cooking" left side first (with the right one being cold) then shortly after it does/"cooks" them both left and right .

Also strange knocking sound appears , but that me thinks is the brake pads "bouncing" in the caliper carrier because the caliper isn't releasing and all expands due to heat .

 

Tried so far :

 

- rebuilt both calipers with full rebuild kit (new pistons too)

- caliper carrier cleaned up round the pad seating surfaces and installed new pad hardware

- slide/guide pins cleaned up and greased with silicon grease , slide/guide pins bores in the carrier too cleaned and inspected

- fitted new lower slide/guide pins bushes (the funny looking anti vibration rubber sleeves , as the old ones where bit swollen)

- new front rubber flex hoses

- got the discs resurfaced/machined (Zimmerman disc with plenty of meat left so , would be silly to throw them away)

- new pads , and all moving areas greased with copper grease

- system bled (no air)

 

All above turned up - good .

 

Took it for a test drive after all that , but still no good , still heating up the fronts .

 

Then , had a look at the master cylinder , took it out and inspected it - seems fine .. no leaks externally or internally , also pedal felt good/firm .

 

Which makes me think ABS pump highly suspicious next and the only left possible problematic part .

There's been recall on a lot of them Opel/Vauxhall Corsa's C and D for faulty ABS pump , but most of what i can find relates to NO braking on one of the front wheels (left one most commonly) , but this one does the opposite drags/wont release .

 

Out of my mind really , i've been up and down round and back like an clown on ecstasy checking rechecking double checking trying testing etc. - nothing seems to work

Unfortunately cant read/see what the ABS does with my scan tool . 

 

 

D

 

 

 

 

 

 

Edited October 7, 2021 by DamirGTI

[Richard309Sri XU5JA 205GTi 8]

1 hour ago, DamirGTI said:

Then , had a look at the master cylinder , took it out and inspected it - seems fine .. no leaks externally or internally , also pedal felt good/firm

Yeah I was going to say I don't reckon it is the master cylinder. Usually would be the opposite symptoms as described, the cylinder seal(s) would go and the brake pressure would "leak" as the fluid goes past the damaged seal. Therefore the pressure on the brakes would slowly fade all the time not stick. 

 

yes ABS control unit/pump/system OR ,maybe did you say this above;

ABS sensors? ABS "rings"? checked/maybe faulty? 

 

On my fiesta 2000 had problems with ABS system as ECU not reading the signal from the ABS rings on the rear rings dirty damaged had to replace.  

 

ABS warning light(s) on the dashboard on?

Edited October 7, 2021 by Richard309Sri XU5JA 205GTi

[DamirGTI 342]

It'll be the ABS pump .

 

Phoned an mate who does diagnostics/mechanotronics , said he did a fair few of them on Corsa's , more common no brake but sticking/binding also same .

 

"Deliberately" left this as an last option till i'm kinda 90% sure (now 100%) , because the replacement ABS units cost serious money , reconditioned also bit expensive , second hand one might be an option on a budget but questionable if it will be good , or if it will for how long ... as it's common problem . 

 

Will see what they want me to do ...

 

D

[Thijs_Rallye 87 4 Cars]

3 hours ago, DamirGTI said:

It's Corsa D , 1.2 16v ("eco flex" engine) , 2012 year .

I've found quite a few similar stories to yours. Apparantly the hydraulic plungers stick in the housing, sometimes applying the ABS can release them for some time. Also seems to happen on BMW 1 series but I do not know for certain if they are the same make of ABS module (MK100 on those)

 

With buying second hand you always have the risk of buying a part with the same problem. Aren't there places where you can have them refurbed? If it helps you I can ask at our breakers over here if they stock something if they are difficult to find for you.

 

[Tom Fenton 1,541]

It’s a known/common fault with the ABS unit

[DamirGTI 342]

Yes , either valves on the pump body or the pressure reg. valve goes bust and causes no brake on one of the front wheels or makes them stick .

Audi , Opel/Vauxhall , BMW , Volvo , VW , Suzuki and some other seems to suffer same/similar ABS failure .

 

Interestingly , doesn't indicate/lit ABS warning light on the instrument cluster . 

 

Apparently , separating it from the module/electronics and putting the stuck/sized pump body in ultrasonic bath and giving it a buzz can free the valves , along with pressure cleaning the ports with isopropyl alcohol or similar .

But if the main pressure reg. valve is bad then , it needs more work done by professional with proper equipment .

 

This one on Opel is Bosch 8.1 ABS version .. guess it's the dirty/old brake fluid which eventually makes them fail/clog (the pump part) , as people rarely (mostly never) replace brake fluid as recommended on a 2 year basis .. kinda like coolant/antifreeze which then turns acidic and attacks/eats the cylinder heads and engine blocks .  

I had a few on which the brake fluid was so old that it turned dark red/black ! thus likely never replaced from when the car was made new , or someone mixed up brake fluid types altogether when topping up and made reaction .

 

Unfortunately , cannot find anyone here who can rebuild them ABS units ..

True , used/second hand one will be 50/50 chances if it will be good , found a few used for around 50-60EUR from breakers .

 

Will need to see with the lady owner , what does she want me to do with this .

 

D

 

 

 

Edited October 7, 2021 by DamirGTI